Dual water heaters

So I am getting ready to plumb my new pottery studio, and I have a question about my idea for water heaters.

This is for a single sink only. I was originally going to put in a small electric tankless. But after reading about how they work, I am not sure if it will work well for my needs. I will sometimes need to have the water running very low, with just enough hot water to make it warm, so I am worried about the heater not getting enough flow to kick on. Also I will have a sprayer that will sometimes be used repeatedly in short bursts. Here I am also worried about getting the cold water sandwich effect.

So my idea is to put in a small tankless, and then a 2.5 gallon tank heater between the tankless and the faucet. The idea being it will act as a capacitor, giving me a steady supply of hot water. But also allowing for large amounts of hot water when needed.